Glass core substrate for integrated circuit devices and methods of making the same

ABSTRACT

Disclosed are embodiments of a glass core substrate for an integrated circuit (IC) device. The glass core substrate includes a glass core and build-up structures on opposing sides of the glass core. Electrically conductive terminals may be formed on both sides of the glass core substrate. An IC die may be coupled with the terminals on one side of the substrate, whereas the terminals on the opposing side may be coupled with a next-level component, such as a circuit board. The glass core may comprise a single piece of glass in which conductors have been formed, or the glass core may comprise two or more glass sections that have been joined together, each section having conductors. The conductors extend through the glass core, and one or more of the conductors may be electrically coupled with the build-up structures disposed over the glass core. Other embodiments are described and claimed.

RELATED APPLICATIONS

The present application is a Continuation of U.S. patent applicationSer. No. 13/442,092, filed Apr. 9, 2012, entitled “GLASS CORE SUBSTRATEFOR INTEGRATED CIRCUIT DEVICES AND METHODS OF MAKING THE SAME”, which isa Divisional of U.S. patent application Ser. No. 12/653,710, filed onDec. 17, 2007, now U.S. Pat. No. 8,207,453, issued Jun. 26, 2012,entitled “GLASS CORE SUBSTRATE FOR INTEGRATED CIRCUIT DEVICES ANDMETHODS OF MAKING THE SAME”.

FIELD OF THE INVENTION

The disclosed embodiments relate generally to substrates for integratedcircuit devices, and more particularly to a substrate having a glasscore.

BACKGROUND OF THE INVENTION

An integrated circuit (IC) die may be disposed in a package to supportthe die, as well as to aid in forming electrical connections between thedie and a next-level component, such as a motherboard, mainboard, orother circuit board. The package typically includes a substrate to whichthe die is both mechanically and electrically coupled. For example, theIC die may be coupled to the substrate by an array of interconnects in aflip-chip arrangement, with a layer of underfill disposed around theinterconnects and between the die and substrate. Each of theinterconnects may comprise a terminal on the die (e.g., a bond pad, acopper pillar or stud bump, etc.) that is electrically coupled (e.g., byreflowed solder) to a mating terminal (e.g., a pad, pillar, stud bump,etc.) on the substrate. Alternatively, by way of further example, the ICdie may be attached to the substrate by a layer of die attach adhesive,and a plurality of wire bonds may be formed between the die andsubstrate.

The IC die is disposed on one side of the substrate, and a number ofelectrically conductive terminals are formed on an opposing side of thesubstrate. The terminals on the opposing side of the substrate will beused to form electrical connections with the next-level component (e.g.,a circuit board), and these electrical connections can be used todeliver power to the die and to transmit input/output (I/O) signals toand from the die. The electrically conductive terminals on thesubstrate's opposing side may comprise an array pins, pads, lands,columns, bumps etc., and these terminals may be electrically coupled toa corresponding array of terminals on the circuit board or othernext-level component. The terminals on the package substrate's opposingside may be coupled to the next-level board using, for example, a socket(and retention mechanism) or by a solder reflow process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram showing a plan view of one embodiment ofa glass core substrate.

FIG. 1B is a schematic diagram showing a cross-sectional elevation viewof the glass core substrate of FIG. 1A, as taken along line B-B of FIG.1A.

FIG. 1C is a schematic diagram showing a portion of the cross-sectionalelevation of FIG. 1B and illustrating another embodiment of a glass coresubstrate.

FIG. 1D is a schematic diagram showing a portion the cross-sectionalelevation of FIG. 1B and illustrating a further embodiment of a glasscore substrate.

FIG. 1E is a schematic diagram showing a portion of the cross-sectionalelevation of FIG. 1B and illustrating yet another embodiment of a glasscore substrate.

FIG. 1F is a schematic diagram showing a portion of FIG. 1E andillustrating yet a further embodiment of a glass core substrate.

FIG. 2 is a schematic diagram showing a cross-sectional elevation viewof an integrated circuit assembly including an embodiment of a glasscore substrate.

FIG. 3 is a block diagram illustrating embodiments of various methods offorming a glass core substrate.

FIGS. 4A-4F are schematic diagrams illustrating embodiments of a methodof forming holes in a glass core.

FIGS. 5A-5C are schematic diagrams illustrating embodiments of analternative method of forming holes in a glass core.

FIGS. 6A-6B are schematic diagrams illustrating embodiments of a furtheralternative method of forming holes in a glass core.

FIGS. 7A-7C are schematic diagrams illustrating embodiments of yetanother alternative method of forming holes in a glass core.

FIGS. 8A-8C are schematic diagrams illustrating embodiments of yet afurther alternative method of forming holes in a glass core.

FIG. 9A is a schematic diagram showing a perspective view of anembodiment of a glass body having embedded metal wires.

FIG. 9B is a schematic diagram showing a side elevation view of theglass body with embedded metal wires shown in FIG. 9A.

FIG. 9C is a schematic diagram showing a perspective view of the cuttingof a slice from the glass body of FIGS. 9A-9B.

FIGS. 10A-10C are schematic diagrams illustrating embodiments of thejoining of two or more slices from the glass body of FIGS. 9A-9B.

FIG. 11A is a schematic diagram showing a perspective view of anotherembodiment of a glass body having embedded metal wires and alignmentelements.

FIG. 11B is a schematic diagram showing a side elevation view of theglass body with embedded metal wires and alignment elements, as shown inFIG. 11A.

FIGS. 11C-11D are schematic diagrams illustrating embodiments of thejoining of two or more slices from the glass body of FIGS. 11A-11B.

FIG. 12 is a schematic diagram illustrating another embodiment of thejoining of sections cut from a glass body having embedded metal wiresand alignment elements.

FIG. 13 is a schematic diagram illustrating a further embodiment of thejoining of sections cut from a glass body having embedded metal wiresand alignment elements.

FIG. 14 is a schematic diagram illustrating yet another embodiment ofthe joining of sections cut from a glass body having embedded metalwires and alignment elements.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed are embodiments of a substrate having a glass core. One ormore build-up layers may be disposed on each side of the glass core, andelectrical conductors extend through the glass core. The glass core maycomprise a single piece of glass, or in other embodiments the glass corecomprises two or more sections of glass that have been joined together.Embodiments of methods of forming a glass core substrate havingconductors extending through the glass core's thickness are describedbelow. Also disclosed are embodiments of an assembly including anintegrated circuit die disposed on a glass core substrate and coupledwith the substrate by a set of interconnects.

As noted above, the disclosed embodiments encompass a substrate having acore comprised of glass. According to one embodiment, the term “glass”refers to an amorphous solid. Examples of glass materials that may beused with the described embodiments include pure silica (e.g.,approximately 100% SiO2), soda-lime glass, boro-silicate glass, andalumo-silicate glass. However, the disclosed embodiments are not limitedto silica-based glass compositions, and glasses having alternative basematerials (e.g., fluoride glasses, phosphate glasses, chalcogen glasses,etc.) may also be employed with the disclosed embodiments. Further, anycombination of other materials and additives may be combined with silica(or other base material) to form a glass having desired physicalproperties. Examples of these additives include not only theaforementioned calcium carbonate (e.g., lime) and sodium carbonate(e.g., soda), but also magnesium, calcium, manganese, aluminum, lead,boron, iron, chromium, potassium, sulfur, and antimony, as well ascarbonates and/or oxides of these and other elements. The aforementionedglasses and additives are but a few examples of the many types ofmaterials and material combinations that may find application with thedisclosed embodiments. In addition, a glass body may include surfacetreatments and/or coatings to improve strength and/or durability, and aglass body may also be annealed to lower internal stresses.

Generally, as used herein, the term “glass” does not refer to organicpolymer materials, which may be amorphous in solid form. However, itshould be understood that a glass according to some embodiments mayinclude carbon as one of the material's constituents. For example,soda-lime glass, as well as numerous variations of this glass type,comprise carbon.

A glass, once formed into a solid body, is capable of being softened andperhaps remelted into a liquid form. The “glass transition temperature”of a glass material is a temperature below which the physical propertiesof the glass are similar to those of a solid and above which the glassmaterial behaves like a liquid. If a glass is sufficiently below theglass transition temperature, molecules of the glass may have littlerelative mobility. As a glass approaches the glass transitiontemperature, the glass may begin to soften and with increasingtemperature the glass will ultimately melt into the liquid state. Thus,a glass body may be softened to an extent sufficient to enablemanipulation of the body's shape, allowing for the formation of holes orother features in the glass body.

According to one embodiment, the “softening temperature” of a glass istemperature at which the glass has softened to an extent sufficient toenable the disclosed embodiments to be performed. For example, in oneembodiment, the softening temperature of a glass is the temperature atwhich the glass is sufficiently soft to allow for formation of holes orother features in the glass by an imprinting technique (to be describedbelow in greater detail). The glass transition and softeningtemperatures are unique properties of a glass, although two or moredifferent glass materials may have similar glass transition and/orsoftening temperatures. Further, it should be understood that the glasstransition temperature and softening temperature of a particular glassmay not necessarily be the same value.

Turning now to FIGS. 1A and 1B, illustrated are embodiments of asubstrate 100 having a core 150 comprised of a glass. A plan view of theglass core substrate 100 is shown in FIG. 1A, whereas a cross-sectionalelevation view of the substrate is shown in FIG. 1B, as taken along lineB-B of FIG. 1A. Also, various alternative embodiments of the glass coresubstrate 100 are shown in each of FIGS. 1C through 1E, and each ofFIGS. 1C through 1E shows a portion of the substrate 100, identifiedgenerally by reference numeral 5 in FIG. 1B, in an enlarged view.

With reference to FIGS. 1A and 1B, the substrate 100 includes a core 150comprised of a glass. Substrate 100 includes a first side 102 and anopposing second side 104 generally parallel with the first side 102. Aperiphery 108 of substrate 100 extends between the first and secondsides 102, 104. According to some embodiments, the periphery 108 of thesubstrate 100 is generally rectangular, and in one embodiment all foursides of the periphery 108 are substantially equal such that theperiphery forms a square. However, it should be noted that a substratehaving a non-rectangular periphery is within the scope of the disclosedembodiments. In one embodiment, the substrate 100 has a thickness ofbetween 0.2 mm and 1 mm.

The glass core 150 has a first surface 152 and an opposing secondsurface 154. In one embodiment, the first and second surfaces 152, 154are generally parallel to each other. A periphery 158 of the glass core150 extends between the first and second surfaces 152, 154, and in someembodiments the glass core's periphery 158 generally corresponds to thesubstrate's periphery 108. According to one embodiment, the glass core150 may have a thickness between 0.1 mm and 0.8 mm. Glass core 150 is,in one embodiment, comprised entirely of glass (other than conductors160, as described below). In a further embodiment, glass core 150comprises a single, solid piece of glass (although the core includesholes for conductors 160). In other embodiments, the glass core 150 maycomprise multiple pieces or sections of glass that have been joinedtogether.

A number of conductors 160 extend through the glass core 150. Eachconductor 160 is disposed in a hole or via 165, and each conductor 160may extend from the first surface 152 to the second surface 154. Inother embodiments, however, one or more of the conductors extends onlypartially through the core's thickness. According to one embodiment, aconductor 160 comprises a hole or via 165 formed through the glass core150 that has been filled with an electrically conductive material. Inanother embodiment, a conductor 160 comprises a hole 165 formed in theglass core during a casting process, and this hole is filled with anelectrically conductive material. In a further embodiment, a conductor160 comprises a metal wire embedded in the glass core 150.

Conductors 160 may comprise any suitable electrically conductivematerial, including metals, composite materials, and electricallyconductive polymers. Suitable metals include copper, tin, silver, gold,nickel, aluminum, and tungsten, as well as alloys of these and/or othermetals. Processes that may be utilized to form a hole or via 165include, for example, imprinting, sand blasting, casting, laserdrilling, and etching. Electrically conductive material may be depositedin the holes or vias 165 to form conductors 160 by any suitable process,such as, for example, screen printing techniques, plating techniques(electroplating or electroless plating), chemical vapor deposition(CVD), and physical vapor deposition (PVD).

Disposed on the first side 102 of substrate 100 is a first set ofelectrically conductive terminals 120 (see FIG. 1A). According to oneembodiment, the first set of terminals 120 is arranged in a pattern tomate with a corresponding array of terminals disposed on an integratedcircuit (IC) die. An IC die is not shown in FIGS. 1A-1B; however, a dieregion 110 is depicted in FIG. 1A and the terminals 120 lie within thisdie region (sometimes referred to as a die shadow region). The terminals120 may each comprise any suitable type of structure capable of formingan electrical connection with a terminal of the IC die. For example, aterminal 120 may comprise a pad, pillar, or stud bump formed from anysuitable metal or combination of metals (e.g., aluminum, copper, nickel,etc.), and a solder bump may be disposed on each terminal 120 (and/or onthe terminals of the IC die). In one embodiment, an IC die may bedisposed on the substrate 100 in a flip-chip manner, and the terminalson the die coupled with the terminals 120 on the substrate 100 by asolder reflow process. According to another embodiment, an IC die may becoupled to the substrate 100 by a layer of adhesive, and terminals onthe die electrically coupled to corresponding terminals on the substrateby a wirebond process (in this embodiment, the terminals 120 would lieoutside the die region 110).

Disposed on the second side 104 of substrate 100 is a second set ofelectrically conductive terminals 125 (only a portion being shown inFIG. 1A for clarity and ease of illustration). According to oneembodiment, the second set of terminals 125 is arranged in a pattern tomate with a corresponding array of terminals disposed on a next levelcomponent, such as a mainboard, a motherboard, or other circuit board(not shown in the figures). The terminals 125 may each comprise anysuitable type of structure capable of forming an electrical connectionwith a terminal of the next-level component. By way of example, aterminal 125 may comprise a pad, land, solder bump or other metal bump,or a pin. The next-level component may include a socket (and retentionmechanism) to receive the substrate 100 and terminals 125, such as aLand Grid Array (LGA) socket or a Pin Grid Array (PGA) socket.Alternatively, the terminals 125 may be coupled with terminals on thenext level component by a solder reflow process.

Disposed on the first surface 152 of glass core 150 is a first build-upstructure 130, and disposed on the core's second surface 154 is a secondbuild-up structure 140. The first build-up structure comprises one ormore alternating layers of a dielectric material and a metal, and theterminals 120 are disposed on the first build-up structure 130 (thefirst substrate side 102 generally corresponding to an outer surface ofthe first build-up structure 130). At least one of the conductors 160 inglass core 150 is electrically coupled with at least one metal layer ofthe first build-up structure 130, and in one embodiment a metal layer ofthe first build-up structure nearest the glass core 150 is coupled withat least one conductor 160. Similarly, the second build-up structure 140comprises one or more alternating layers of a dielectric material and ametal, and the terminals 125 are disposed on the second build-upstructure 140 (the second substrate side 104 generally corresponding toan outer surface of the second build-up structure 140). At least one ofthe conductors 160 in glass core 150 is electrically coupled with atleast one metal layer of the second build-up structure 140, and in oneembodiment a metal layer of the second build-up structure nearest theglass core 150 is coupled with at least one conductor 160. The first andsecond build-up structures 130, 140 route power, as well as input/output(I/O) signals, between the first and second sets of terminals 120, 125(and, hence, facilitate the delivery of power and signaling between anIC die mounted on substrate 100 and a next-level component). Build-upstructures 130, 140 are described in greater detail below.

Referring to FIG. 1C, an embodiment of the glass core substrate 100 isillustrated in greater detail. As previously described, the substrateincludes a glass core 150 having conductors 160 extending between firstand second surfaces 152, 154, respectively, of the core. Each of theconductors 160 may be disposed in a hole or via 165 extending throughthe glass core 150. A first build-up structure 130 is disposed on thefirst side 152 of the core 150, and a second build-up structure 140 isdisposed on the core's opposing second side 154.

According to one embodiment, first build-up structure 130 comprises anumber of dielectric material layers 133 a, 133 b, 133 c, 133 d, and anumber of metal layers 136 a, 136 b, 136 c. Dielectric layers 133 a-dmay comprise any suitable dielectric material (e.g., polymer materials,etc.) and may be formed by any suitable technique (e.g., by deposition,lamination, etc.). Metal layers 136 a-c may comprise any suitableelectrically conductive metal (e.g., copper, aluminum, silver, etc.),and may be deposited by any suitable technique (e.g., plating processes,such as electroplating and electroless plating). Further, the metallayers 136 a-c may each be patterned to form any suitable number andconfiguration of traces, power planes, ground planes, and otherconductors to facilitate the routing of power and I/O signals.

One of the dielectric layers 133 a-d is disposed between any twoadjacent metal layers 136 a-c (e.g., metal layers 136 a and 136 b areseparated by dielectric layer 133 b, and so on), and dielectric layer133 a lies adjacent the glass core 150 and separates the metal layer 136a from the core. According to one embodiment, the dielectric layer 133 alies directly adjacent the glass core's first surface 152. Vias 139 a,139 b, 139 c—which are plated or filled with metal—extend through thedielectric layers 133 a, 133 b, 133 c, respectively, and interconnectadjacent metal layers (e.g., vias 139 b interconnect metal layers 136 aand 136 b, and so on). Further, the metal layer 136 a nearest the glasscore 150 is coupled with one or more of the conductors 160 by vias 139 adisposed in dielectric layer 133 a. In one embodiment, the first surface152 of glass core 150 may include a surface treatment or coating toincrease adhesion with the dielectric material of the build-up structure130. Also, in some embodiments, the outermost dielectric layer 133 d maycomprise a resist layer and/or a passivation layer. Also, according toone embodiment, terminals 120 are formed by, or formed on, the outermostmetal layer 136 c.

In one embodiment, second build-up structure 140 comprises a number ofdielectric material layers 143 a, 143 b, 143 c, 143 d, and a number ofmetal layers 146 a, 146 b, 146 c. Dielectric layers 143 a-d may compriseany suitable dielectric material (e.g., polymer materials, etc.) and maybe formed by any suitable technique (e.g., by deposition, lamination,etc.). Metal layers 146 a-c may comprise any suitable electricallyconductive metal (e.g., copper, aluminum, silver, etc.), and may bedeposited by any suitable technique (e.g., plating processes, such aselectroplating and electroless plating). Further, the metal layers 146a-c may each be patterned to form any suitable number and configurationof traces, power planes, ground planes, and other conductors tofacilitate the routing of power and I/O signals.

One of the dielectric layers 143 a-d is disposed between any twoadjacent metal layers 146 a-c (e.g., metal layers 146 a and 146 b areseparated by dielectric layer 143 b, and so on), and dielectric layer143 a lies adjacent the glass core 150 and separates the metal layer 146a from the core. According to one embodiment, the dielectric layer 143 alies directly adjacent the glass core's second surface 154. Vias 149 a,149 b, 149 c—which are plated or filled with metal—extend through thedielectric layers 143 a, 143 b, 143 c, respectively, and interconnectadjacent metal layers (e.g., vias 149 b interconnect metal layers 146 aand 146 b, and so on). Further, the metal layer 146 a nearest the glasscore 150 is coupled with one or more of the conductors 160 by vias 149 adisposed in dielectric layer 143 a. In one embodiment, the secondsurface 154 of glass core 150 may include a surface treatment or coatingto increase adhesion with the dielectric material of the build-upstructure 140. Also, in some embodiments, the outermost dielectric layer143 d may comprise a resist layer and/or a passivation layer. Inaddition, in one embodiment, terminals 125 are formed by, or formed on,the outermost metal layer 146 c.

In the embodiment of FIG. 1C (as well as the embodiments shown in eachof FIGS. 1D and 1E), the first and second build-up structures have thesame number of dielectric and metal layers and, further, have generallyequivalent thicknesses. However, the disclosed embodiments are not solimited, and in other embodiments the first and second build-upstructures may have differing thicknesses and/or differing numbers ofdielectric and metal layers. According to another embodiment, a build-upstructure is disposed on only one side of the glass core 150. Also, insome embodiments, the first and second build-up structures areconstructed from the same dielectric material and metal. In otherembodiments, however, the first and second build-up structures may havediffering materials.

In the embodiment of FIG. 1C, dielectric layers 133 a and 143 a arepositioned adjacent the glass core 150, and the metal layers nearest thecore (i.e., metal layers 136 a and 146 a) are separated from the core bythese dielectric layers. In an alternative embodiment, as illustrated inFIG. 1D, a metal layer may lie adjacent the glass core 150. Theincorporation of a metal layer adjacent one or both sides of the glasscore 150 is sometimes referred to as “core layer routing.”

Referring to FIG. 1D, the embodiment of substrate 100 is generallysimilar to that shown in FIG. 1C (and like features are identified bythe same reference numerals). However, in the embodiment of FIG. 1D, thefirst build-up structure 130 includes a metal layer 136 x adjacent theglass core 150, and according to one embodiment the metal layer 136 x isdirectly adjacent the glass core's first surface 152. Dielectric layer133 a overlies the metal layer 136 x (and exposed portions of the glasscore), this metal layer 136 x now being the metal layer nearest thecore, and at least one of the conductors 160 is coupled with metal layer136 x. Further, in another embodiment, the first surface 152 of glasscore 150 may include a surface treatment or coating to increase adhesionwith the metal layer 136 x (and perhaps with portions of dielectriclayer 133 a).

Similar to first build-up structure 130, the second build-up structure140 of FIG. 1D includes a metal layer 146 x adjacent the glass core 150,and in one embodiment the metal layer 146 x is directly adjacent theglass core's second surface 154. Dielectric layer 143 a overlies themetal layer 146 x (and exposed portions of the glass core), this metallayer 146 x now being the metal layer nearest the core, and at least oneof the conductors 160 is coupled with metal layer 146 x. In addition, inanother embodiment, the second surface 154 of glass core 150 may includea surface treatment or coating to increase adhesion with the metal layer146 x (and perhaps with portions of dielectric layer 143 a). In someembodiments, only one of the glass core's surfaces 152, 154 has anadjacent metal layer (e.g., either one of metal layers 136 x, 146 x inthe first and second build-up structures 130, 140, respectively, may beomitted).

With reference now to FIG. 1E, a further embodiment of glass coresubstrate 100 is illustrated. The embodiment of substrate 100 show inFIG. 1E is generally similar to that shown in FIG. 1C (and like featuresare identified by the same reference numerals). However, in theembodiment of FIG. 1E, the hole or via 165 in which each conductor 160is disposed has a wall that is tapered. In one embodiment, the taperedwall of hole or via 165 has an angle 167 relative to a centerline of thehole of between 0 and 30 degrees. The tapered wall of a hole 165 may bethe result of the process used to form the hole through the glass core150. As noted above, processes that may be utilized to form a hole orvia 165 include, for example, imprinting, sand blasting, casting, laserdrilling, and etching. Depending upon the processing conditions, any oneof the aforementioned techniques may form a hole 165 having a taperedwall.

Turning next to FIG. 1F, a further embodiment of the glass coresubstrate 100 is illustrated. A portion of the substrate 100, as denotedgenerally by reference numeral 7 in FIG. 1E, is shown in FIG. IF in anenlarged view (with like features being identified by the same referencenumeral). In the embodiment of FIG. 1F, a wetting layer (or adhesionlayer) 170 has been disposed over the wall 165 of hole 160. The functionof wetting layer 170 is to increase adhesion between the electricallyconductive material 160 and the glass material of core 150, and thewetting layer 170 may comprise any suitable material capable ofincreasing adhesion between these two materials. In one embodiment, thewetting layer 170 comprises a metal, such as, for example, titanium,chromium, nickel, and vanadium, as well as alloys of these and/or othermetals. Also, the wetting layer 170 may be deposited or formed using anysuitable process, such as a plating technique (electroplating orelectroless plating), CVD, or PVD.

Illustrated in FIG. 2 is an embodiment of an assembly 200 including aglass core substrate 100. With reference to FIG. 2, the assembly 200includes substrate 100 having glass core 150, as well as a first side102 and an opposing second side 104. Disposed on the substrate's firstside 102 is an integrated circuit (IC) die 210. The IC die 210 iselectrically (and mechanically) coupled with the substrate 100 by anumber of interconnects 220. Terminals 125 (e.g., lands, pins, solderbumps, etc.) on the substrates second side 104 (see FIG. 1A) may be usedto form electrical connections with a next-level component, such as amotherboard, mainboard, or other circuit board. A heat spreader or lid230—having a first surface 232 and an opposing second surface 234 thatfaces a back surface 215 of the die—is disposed over the die 210 andthermally coupled with (and perhaps mechanically coupled with) the die'sback surface 215 by a layer of thermal interface material 240. Anadhesive or sealant 290 may be used to secure the heat spreader 230 tothe first surface 102 of glass core substrate 100. Although not shown inFIG. 2, in a further embodiment a heat sink (or other cooling device)may be thermally coupled with the heat spreader 230, and another layerof a thermal interface material may be disposed between the heatspreader's first surface 232 and the heat sink (or other device).

IC die 210 may comprise any type of semiconductor device. In oneembodiment, the IC die 210 comprises a processing system or device. Forexample, IC die 210 may comprise a microprocessor or a graphicsprocessor. The IC die 210 can perform instructions from any number ofprocessor architectures having any number of instruction formats. In oneembodiment, an instruction is an “x86” instruction, as used by IntelCorporation. However, in other embodiments, the processor may performinstructions from other architectures or from other processor designers.In another embodiment, the IC die 210 comprises a memory device.According to a further embodiment, the IC die 210 comprises asystem-on-chip (SoC). In yet another embodiment, the IC die 210 mayinclude digital circuitry, analog circuitry, or a combination of bothanalog and digital circuitry.

Interconnects 220 are formed by coupling terminals 120 on the substratefirst surface 102 (see FIG. 1A) with terminals on the IC die 210 by, forexample, a solder reflow process. As previously described, the substrateterminals 120 may each comprise a pad, pillar, or stud bump formed fromany suitable metal or combination of metals (e.g., copper, nickel,aluminum, etc.), and the die terminals may also comprise a pad, pillar,or stud bump formed from any suitable metal or combination of metals.Solder (e.g., in the form of balls or bumps) may be disposed on thesubstrate and/or die terminals, and these terminals may then be joinedusing a solder reflow process. It should be understood that theaforementioned interconnects are but one example of the type ofinterconnects that can be formed between substrate 100 and IC die 210and, further, that any other suitable type of interconnect may beutilized. In addition, a layer of underfill material (not shown in FIG.2) may be disposed around the interconnects 220 and between the IC die210 and the substrate's first side 102.

Heat spreader 230 may be comprised of any suitable thermally conductivematerials and may have any suitable shape or structure. According to oneembodiment, the heat spreader 230 comprises a lid having a side wall (orwalls) 237 extending towards the substrate's first side 102, with thiswall (or walls) being secured to the substrate surface 102 by theadhesive 290. The above-describe lid is sometimes referred to as anintegrated heat spreader, or IHS. Materials that may be used toconstruct the heat spreader 230 include metals (e.g., copper and alloysthereof), thermally conductive composites, and thermally conductivepolymers.

In the embodiment illustrated in FIG. 2, the assembly 200 includes asingle IC die 210. However, in other embodiments, the assembly 200 maycomprise a multi-chip package. For example, one or more other integratedcircuit die (e.g., a memory device, a voltage regulator, etc.) may bedisposed on the substrate 100. In addition, passive devices, such ascapacitors and inductors, may be disposed on the glass core substrate100 or, alternatively, integrated into the build-up structures 130, 140of the substrate. By way of example, an array capacitor or a thin-filmcapacitor may be integrated into the build-up structures 130, 140 of thesubstrate 100. In another embodiment, a wireless component, such as anantenna or an RF shield, may be disposed on glass core substrate 100 orintegrated into the build-up structures 130, 140 of this substrate.These additional devices, whether IC die, passive devices, or othercomponents, may be disposed on either side 102, 104 of the glass coresubstrate 100.

The assembly 200 may form part of any type of computing device.According to one embodiment, the assembly 200 may form part of a serveror desktop computer. In another embodiment, the assembly 200 forms partof a lap-top computer or similar mobile computing device (e.g., anet-top computer). In a further embodiment, the assembly 200 comprisespart of a hand-held computing device, such as a cell phone, a smartphone, or a mobile interne device (MID). In yet another embodiment, theassembly 200 forms part of an embedded computing device.

Illustrated in FIG. 3 are embodiments of various methods of making aglass core substrate. These various methods and embodiments thereof arefurther illustrated in FIGS. 4A-4F, FIGS. 5A-5C, FIGS. 6A-6C, FIGS.7A-7C, FIGS. 8A-8C, FIGS. 9A-9C, FIGS. 10A-10C, FIGS. 11A-11D, FIG. 12,FIG. 13, and FIG. 14, and reference should be made to these figures ascalled out in the text below.

Referring to block 305 in FIG. 3, in one embodiment a glass plate isprovided. This is illustrated in FIG. 4A, where a glass plate 410 isshown. The glass plate includes a first surface 412 and an opposingsecond surface 414 that is generally parallel with first surface 412.Glass plate 410 may comprise any suitable type of glass and have anysuitable thickness (see discussion above), depending upon theapplication and/or desired characteristics. According to one embodiment,the glass plate 410 is of a size and configuration to enable formationof a single substrate. In a further embodiment, the glass plate 410 isof a size and configuration to enable the formation of two or moresubstrates (e.g., the glass plate 410 comprises a panel from which twoor more substrates will be cut). Plate 410 will have a softeningtemperature associated with the glass material comprising this plate.

As set forth in block 310 of FIG. 3, holes or vias are formed in theglass plate. This is further illustrated in FIG. 4B, where holes 420have been formed in glass plate 410, each hole extending from the firstsurface 412 to the plate's second surface 414. In other embodiments, oneor more of the holes or vias 420 may not extend entirely through thethickness of the glass plate 410. Various methods may be implemented toform the holes 420. In one embodiment, the holes are formed by a planarimprinting technique (see FIGS. 5A-5C). In another embodiment, the holesare formed by a roller imprinting technique (see FIGS. 6A-6B). In afurther embodiment, the holes are formed by a sand blasting (or powerblasting or particle blasting) technique (see FIGS. 7A-7C). Each ofthese embodiments for forming holes 420 will now be described in greaterdetail. It should be understood, however, that the disclosed embodimentsare not limited to the hole formation techniques described in FIGS. 5Athrough 7C and, further, that other methods may be employed to formholes in a glass plate (e.g., laser drilling, etching, etc.).

Turning to FIG. 5A, an imprinting tool 510 is shown in conjunction withglass plate 410. A number of protrusions 520 extend from imprinting tool510, and each of these protrusions is sized, oriented, and located tocreate one of the holes or vias 420 in glass plate 410. The imprintingtool 510 may comprise any suitable material capable of forming the holesin the glass material of plate 410 and withstanding the associatedprocessing temperatures. In one embodiment, surfaces of the imprintingtool 510 and protrusions 520 may include a coating or surface treatmentto minimize adhesion with the glass material (e.g., to prevent stickingbetween the tool and glass).

Referring to FIG. 5B, the glass plate 410 is raised to the softeningtemperature, and the protrusions 520 of imprinting tool 510 are plungedinto the glass plate 410. Protrusions 520 will form holes 420 in thesoftened glass plate 410. The time required to heat glass plate 410 tothe softening temperature, as well as the amount of time the plate ismaintained at this temperature while engaged with the imprinting tool510, are dependent upon, for example, the glass material comprisingplate 410, the desired characteristics of the final glass core, and theprocessing equipment being utilized.

Referring next to FIG. 5C, the imprinting tool 510 has been removed andthe plate 410 cooled to return the glass material to a solid state.Holes 420 remain in the glass plate 410 at locations corresponding toprotrusions 520 on imprinting tool 510. In one embodiment, afterimprinting, an annealing process may be performed to relieve internalstresses within glass plate 410.

Turning now to FIGS. 6A and 6B, a roller imprinting tool 610 is shown inconjunction with glass plate 410. A number of protrusions 620 extendfrom the roller imprinting tool 610, and each of these protrusions issized, oriented, and located to create one of the holes or vias 420 inglass plate 410. Note that, for clarity and ease of illustration, only aportion of the protrusions 620 on tool 610 are shown in FIGS. 6A-6B(e.g., protrusions 620 may extend about the full circumference of tool610). Roller imprinting tool 610 may rotate about an axis 605, and theglass plate 410 may rest on a support plate or carrier 630 that iscapable of moving relative to tool 610 (or, alternatively, tool 610 iscapable of moving relative to support plate 630). The imprinting tool610 may comprise any suitable materials capable of forming the holes inthe glass material of plate 410 and withstanding the associatedprocessing temperatures. In one embodiment, surfaces of the imprintingtool 610 and protrusions 620 may include a coating or surface treatmentto minimize adhesion with the glass material.

The glass plate 410 is raised to the softening temperature, and theprotrusions 620 of imprinting tool 610 are engaged with glass plate 410.The roller imprinting tool 610 is engaged with glass plate 410 by movingthe glass plate relative to tool 610 (see arrow 8) while rotating thetool 610 about axis 605 (see arrow 9). Protrusions 620 will form holes420 in the softened glass plate 410. The time required to heat glassplate 410 to the softening temperature, as well as the amount of timethe plate is maintained at this temperature while engaged with theimprinting tool 610, are dependent upon, for example, the glass materialcomprising plate 410, the desired characteristics of the final glasscore, and the processing equipment being utilized. After the glass plate410 has engaged with the roller imprinting tool 610, the plate 410 iscooled to return the glass material to a solid state. Holes 420 remainin the glass plate at locations corresponding to protrusions 620 onimprinting tool 610. In one embodiment, after imprinting, an annealingprocess may be performed to relieve internal stresses within glass plate410.

With reference to FIG. 7A, a layer of resist material 710 has beendisposed on the first surface 412 of glass plate 410, and this resistlayer 710 has been patterned to form openings 720. A sand blastingprocess will be performed on the glass plate 410, and the resist layer710 may comprise any material capable of withstanding the sand blastingprocess (e.g., the resist layer is substantially impervious to the sandblasting process or, alternatively, the resist layer is removed by thesand blasting process at a lower rate then the glass material isremoved). The resist layer material should also be amendable to apatterning technique (e.g., photolithography) to enable formation ofopenings 720.

Referring to FIG. 7B, a sand blasting process (which may also bereferred to as powder blasting or particulate blasting) is performed onthe glass plate 410 having patterned resist layer 710. Any suitable sandblasting technique and tools may be employed using any suitable sand orparticulate 730. The particulate used will depend upon the toolsemployed, the process characteristics, and the glass material comprisingplate 410. The moving particulates 730 will remove those portions of theglass plate exposed by openings 720 in resist layer 710. The movingparticulates 730 may also attack the resist material 720, but at a lowerrate than the glass substrate 410, allowing for the formation of holes420 at only locations of openings 720. Sand blasting may continue untilthe holes 420 extend through the glass plate 410 from first surface 412to second surface 414 (although it is within the scope of the disclosedembodiments that one or more of the holes 420 does not extend entirelythrough the glass plate 410). After sand blasting is complete, as shownin FIG. 7C, the resist material 720 is removed, and holes 420 have beenformed in glass plate 410.

Returning now to FIG. 3, and block 315 in particular, in one embodimenta wetting or adhesion layer may be formed over walls of the vias. Thisis illustrated in FIG. 4C, where a layer of wetting material 430 hasbeen disposed over the walls 425 of holes 420, as well as over the firstsurface 412 of glass plate 410. Any suitable blanket deposition processmay be employed to form wetting layer 430, such as a plating technique(electroplating or electroless plating), CVD, or PVD. The wettingmaterial 430 is then removed from the glass plate's first surface 412,such that the wetting material 430 remains only on the walls 425 of vias420, as shown in FIG. 4D. The excess wetting material 430 may be removedfrom the surface 412 by, for example, a grinding process orchemical-mechanical polishing technique.

As set forth above, the function of wetting layer 430 is to increaseadhesion between the glass material of plate 410 and an electricallyconductive material that is to be deposited in holes 420, and thewetting layer 430 may comprise any suitable material capable ofincreasing adhesion between these materials. In one embodiment, thewetting layer 430 comprises a metal, such as, for example, titanium,chromium, nickel, or vanadium, as well as alloys of these and/or othermetals. However, in other embodiments, a wetting layer is not depositedon the surfaces of the vias 420 in glass plate 410 (i.e., the stepcorresponding to block 315 may be omitted).

As set forth in block 320, the holes in the glass plate are filled withan electrically conductive material to form conductors extending throughthe glass plate. This is illustrated in FIG. 4E, wherein an electricallyconductive material 440 has been disposed in holes 420. In theembodiment of FIGS. 4A-4F, the conductive material 440 is disposed onthe wetting layer 430, but as noted above in other embodiments such awetting layer may not be present. The electrically conductive material440 may be deposited in the vias 420 by any suitable process, such as,for example, screen printing techniques, plating techniques(electroplating or electroless plating), CVD, or PVD. The material 440forming conductors in glass plate 410 may comprise any suitableelectrically conductive material, including metals, composite materials,and electrically conductive polymers. Suitable metals include copper,tin, silver, gold, nickel, aluminum, and tungsten, as well as alloys ofthese and/or other metals. In one embodiment, any of these metals may bedeposited in paste or particle form (e.g., where a screen printingtechnique used), and a sintering process may be performed after pastedeposition.

Referring to block 390, one or more build-up layers is disposed on eachside of the glass plate (or perhaps only one side) to create build-upstructures, as previously described. This is shown in FIG. 4F, where afirst build-up structure 450 has been formed on the first surface 412 ofglass plate 410, and a second build-up structure 460 has been formed onthe glass plate's second surface 414. Each build-up structure 450, 460may comprise any suitable number of alternating layers of dielectricmaterial and metal (e.g., one or more), and they may be formed by anysuitable techniques. The structure and formation of such build-upstructures is described in greater detail with reference to FIGS. 1Bthrough 1F and the accompanying text above. In one embodiment, at leastone of the conductors 440 is electrically coupled with a metal layer ofthe first build-up structure that is nearest the glass plate 410, and ina further embodiment at least one of the conductors 440 is electricallycoupled with a metal layer of the second build-up structure that isnearest the glass plate.

With reference to block 395, electrically conductive terminals may beformed on the glass plate (terminals are not shown in FIGS. 4A-4F). Afirst set of terminals may be formed on the first build-up structure450, and a second set of terminals may be formed on the second build-upstructure 460. The structure and formation of such terminals isdescribed in greater detail with reference to FIGS. 1A through 1F andthe accompanying text above.

As noted above, in one embodiment, the glass plate 410 includesstructures and features corresponding to two or more substrates. In thisembodiment, the glass plate 410 with build-up structures 450, 460 may besingulated into these discrete substrates (either before or afterformation of the terminals).

Turning now to block 325 in FIG. 3, in another embodiment, a glass corewith holes is formed by a casting process. An embodiment of a castingprocess is shown in FIGS. 8A-8C. Referring to FIG. 8A, a casting mold810 includes a number of protrusions 820, each protrusions 820 beingsized, oriented, and located to create one of the holes or vias in amolded glass plate. The casting mold 810 may comprise any suitablematerial capable of withstanding the processing temperatures associatedwith molten glass. In one embodiment, surfaces of the casting mold 810and protrusions 820 may include a coating or surface treatment tominimize adhesion with the glass material (e.g., to prevent stickingbetween the mold and glass).

Referring to FIG. 8B, a glass material 405, which has been heated to themelt temperature for a time sufficient to transform the glass into amolten liquid state, is disposed in the mold 810. The molten glass flowsinto the mold 810 and around protrusions 820, such that holes will beformed at locations corresponding to protrusions 820. The glass is thencooled to a solid state and then removed from the mold 820, providing acast glass plate 410 having holes 420, as shown in FIG. 8C. The time andtemperature profile employed to both heat and cool the glass will bedependant upon the glass material being used as well as the desiredproperties of the final glass plate. In one embodiment, after casting,an annealing process may be performed to relieve internal stresseswithin glass plate 410.

After casting of glass plate 410 having holes 420, a glass coresubstrate may be fabricated, as described above with respect to blocks315, 320, 390, and 395. Again, a wetting layer, as shown in block 315,may be omitted in some embodiments.

Referring to block 330 in FIG. 3, in yet a further embodiment, a glasscore is formed by providing a glass body having embedded conductivewires. This is further illustrated in FIGS. 9A and 9B, which show aglass body 910 having embedded wires 920. The wires 920 are disposedwithin holes 930, wherein the holes 930 may be formed during the processof embedding the wires 920 within the glass body 910. Wires 920 maycomprise any suitable electrically conductive material (e.g., copper,aluminum, nickel, as well as alloys of these and/or other metals). Glassbody 910 may comprise any suitable glass material and may be formedusing any suitable process or combination of processes. According to oneembodiment, the wires 920 are embedded during the same process in whichglass body 910 is formed. For example, the glass body 910 havingembedded wires 920 (within holes 930) may be formed using an extrusionprocess. In one embodiment, where a glass body 910 having embedded wires920 is utilized for glass core fabrication, via formation and metal fillprocesses can be omitted.

In one embodiment, the glass body 910 has a generally rectangularparallel-piped shape. Glass body may have a surface 912 a and anopposing surface 912 b that is generally parallel with surface 912 a, asurface 914 a and an opposing surface 914 b that is generally parallelwith surface 914 a, and a surface 916 a and an opposing surface 916 bthat is generally parallel with surface 916 a. The wires 920 (and holes930) extend from surface 912 a through the glass body 910 to opposingsurface 912 b, and the wires may be generally parallel with surfaces 914a-b and 916 a-b. Although shown as generally circular in cross-section,the wires 920 may have any other suitable shape (e.g., oval, square,hexagonal, etc.). Also, when viewed from the side (see FIG. 9B), theglass body 910 has a rectangular cross-section; however, it should beunderstood that the disclosed embodiments are not limited to arectangular or square cross-section (e.g., the glass body 910 may have acircular or oval cross-section, etc.).

Referring to block 335, one or more slices are cut from the glass body.This is illustrated in FIG. 9C, where a cutting tool and/or process 950is applied to the glass body 910 to cut a slice 940. Slice 940 has afirst side 942 and an opposing second side 944 that is generallyparallel with first side 942. Also, portions of the embedded wires 920remain in the slice 940 and extend from the first side 942 to the secondside 944 (for clarity, the hidden lines associated with the extension ofwires 920 through the thickness of slice 940 are shown for only aportion of the wires in FIG. 9C). Any suitable cutting tool or methodmay be employed to cut a slice 940 from glass body 910, such as lasercutting or mechanical sawing. In one embodiment, after cutting, anannealing process may be performed to relieve internal stresses withinglass slice 410.

The slice 940 having embedded wire portions 920 may be used to constructa glass core for a substrate, with the wire portions 920 providingconductors through the glass core's thickness. Utilizing a structurehaving embedded wires as conductors eliminates the processes of viaformation (e.g., see block 310) and via metal fill (e.g., see block 320and 315). In one embodiment, as set forth in block 340 of FIG. 3, asingle slice 940 may be used as the glass core for a substrate. One ormore build-up layers may be formed on the first and second side 942, 944of the core 940 (or perhaps only one side o the core), and terminals mayalso be formed on the build-up structures (see blocks 390 and 395, aswell as the accompanying text above).

In another embodiment, as set forth in block 345, two or more slices cutfrom the glass body may be joined together to form a glass core. This isfurther illustrated in FIGS. 10A and 10B, which show two slices 940 aand 940 b cut from glass body 910, each having embedded wires 920extending through their respective thicknesses (as before, the hiddenlines associated with wires 920 are shown for only a portion of thewires for clarity). The two glass slices 940 a, 940 b are joinedtogether along the two facing edges 914 a, 914 b of slices 940 a, 940 b,respectively, to form a glass core 1002 having conductors 920. Anysuitable process may be employed to join or fuse the two slices 940 a,940 b together. For example, the slices 940 a-b may be brought togetherunder elevated temperature (e.g., at or above the softening temperature)and/or pressure to fuse the two glass pieces together. Alternatively,the slices 940 a-b may be joined using an adhesive.

In FIGS. 10A and 10B, two slices 940 a-b cut from glass body 910 werejoined together to create a glass core. However, it should be understoodthat any suitable number of slices can be joined together to create aglass core having any desired size. By way of example, as shown in FIG.10C, three slices 940 c, 940 d, 940 e may be joined together to form aglass core 1003. Embedded wires 920 extend through the thickness of theglass core 1003.

Irrespective of the number of glass slices being joined, after theslices have been fused together into a glass core 1002 or 1003, thesubstrate fabrication process may continue as previously described. Oneor more build-up layers may be formed on the opposing sides of the core1002 or 1003 (or perhaps only one side thereof), and terminals may alsobe formed on the build-up structures (see blocks 390 and 395, as well asthe accompanying text above).

Referring to block 350, in another embodiment, alignment elements areprovided. This is illustrated in FIGS. 11A and 11B, where matingalignment elements 1150, 1160 have been disposed on glass body 910 (likefeatures between FIGS. 9A-9C and FIGS. 11A-11D retaining the samenumerical designation in FIGS. 11A-11D). Where two or more glass slicesare being joined to form a core, the alignment elements 1150, 1160 canbe used to align and orient the slices relative to each other during thejoining process. The mating alignment elements may comprise anystructures or features capable of aligning and/or orienting one glassslice relative to another glass slice, and any suitable number of matingalignment features may be disposed on the glass body 910 (and, hence,any slice cut from the glass body). In the illustrated embodiment, thereare two alignment elements 1150, each comprising a wire partiallyembedded in (or otherwise adhered to) the surface 914 b of glass body910. Further, there are two alignment elements 1160, and each comprisesa notch formed in the glass body's opposing surface 914 a. Again,however, there may be any suitable number of mating alignment elements(e.g., three or more mating pairs, etc.).

The alignment elements 1150, 1160 may be formed on, or disposed on, theglass body 910 using any suitable technique. According to oneembodiment, the alignment elements 1150 are disposed on the glass body910 during the same process in which wires 920 are embedded, and in afurther embodiment the alignment elements 1160 are also formed duringthe same process that creates glass body 910 (e.g., wires 920 and 1150may be disposed on glass body 910 during an extrusion process that alsoresults in formation of notches 1160). However, in other embodiments,either of the alignment elements 1150 or 1160 may be disposed on glassbody 910 by separate processes (e.g., notches 1160 may be formed afterextrusion by a grinding or cutting process, wires 1150 may be disposedon glass body 910 using adhesive, etc.). Also, the alignment elementsmay comprise any suitable materials capable of withstanding anysubsequent processing temperatures. In the illustrated embodiment, thewires 1150 may comprise a metal, such as tungsten, molybdenum, ornickel, as well as alloys of these and/or other metals. According to oneembodiment, the wires 1150 comprises the same metal as embedded wires920. According to another embodiment, the wires 1150 comprise a metalhaving a CTE approximately the same as the glass material of body 910.

The glass body 910 having alignment elements 1150, 1160 is then cut intoslices (see block 335), as previously described. Two or more of theseslices can then be joined to form a glass core for a substrate (seeblock 345). For example, as shown in FIG. 11C, two slices 940 a and 940b have been joined to form glass core 1102. During joining of glassslices 940 a, 940 b, the alignment elements 1150, 1160 engage to alignthese two pieces relative to one another. By way of further example, asshown in FIG. 11D, three sections 940 c, 940 d, and 940 e have beenjoined to form glass core 1103. Again, the mating alignment elements1150, 1160 of the three sections 940 c-e engage and align these threepieces relative to each other.

Irrespective of the number of glass slices being joined, after theslices have been fused together into a glass core 1102 or 1103, thesubstrate fabrication process may continue as previously described. Oneor more build-up layers may be formed on the opposing sides of the core1102 or 1103 (or perhaps only one side thereof), and terminals may alsobe formed on the build-up structures (see blocks 390 and 395, as well asthe accompanying text above).

In the embodiments of FIGS. 11A through 11D, the alignment wires 1150were disposed within the array of conductors 920. According to oneembodiment, the alignment wires 1150 may be utilized as conductorsthrough the glass core (e.g., the alignment wires 1150 may servefunctions similar to conductors 920). However, in other embodiments, thealignment elements may be located outside the array of conductors, andin yet another embodiment the alignment elements may be removed afterjoining is complete. The aforementioned embodiments are illustrated inFIG. 12, which shows five glass slices or sections 1201, 1202, 1203,1204, and 1205 that have been joined together to form a glass core 1200.A number of conductors 1220 extend through each of the glass sections1201-1205. Each slice of glass 1201-1205 also includes mating alignmentelements 1250, 1260, which have been utilized to align the glasssections 1201-1205 during the joining process. The alignment elements1250, 1260 are positioned outside the array of conductors 1220. In oneembodiment, after glass joining has been performed to create core 1200,portions of the glass core including the alignment elements 1250, 1260may be removed. For example, the glass core 1200 may be cut along linesX-X and Y-Y to remove the alignment features 1250, 1260, and anysuitable cutting process may be employed to remove these portions of thecore (e.g., laser cutting, sawing, etc.).

In the embodiments previously described, the alignment elements comprisea round wire and a mating triangular-shaped notch. However, it should beunderstood that the aforementioned alignment elements may have anysuitable shape and configuration. For example, as shown in FIG. 13, twoglass slices 1301 and 1302 are to be joined together, and each sliceincludes alignment features 1350 and 1360. Alignment features 1350comprise a wire, and alignment features 1360 comprise a semi-circularnotch sized to receive one of the wires 1350. By way of further example,as shown in FIG. 14, two glass sections 1401 and 1402 are to be joinedtogether, with each slice having alignment elements 1450 and 1460.Alignment features 1460 comprise notches (in this instance,semi-circular in shape), but the alignment elements 1450 compriseprotrusions formed directly on the glass sections 1401, 1402 (theprotrusion in this example also being semi-circular in shape). In theembodiment of FIG. 14, it is not necessary to attach separate alignmentfeatures (e.g., alignment wires), and both mating alignment features1450, 1460 may be formed during an extrusion process utilized to createthe glass body (having embedded wires) from which the slices 1401, 1402are cut.

At this juncture, it should be noted that the figures are schematicdiagrams provided as an aide to understanding the disclosed embodiments,and no unnecessary limitations should be implied from the figures. Insome instances, a relatively small number of features may have beenillustrated for clarity and ease of illustration. For example, thenumber of conductors 60 (or 440, 920, 1220) extending through the glasscore 150 (or 410, 1002, 1003, 1102, 1103, 1200) shown in the figures maybe substantially less than a number of conductors that may, in practice,be disposed in such a glass core. Also, the figures may not be drawn toscale, and in some cases lines (e.g., hidden lines) have been omittedfor ease of understanding.

Glass materials may have a CTE of approximately 3.2 ppm, although theCTE value is temperature dependent and will also vary depending upon thecomposition of any particular glass material. Silicon may have a CTE ofapproximately 2.6 ppm, which again is temperature dependent. Organicpolymer-based materials typically used in the construction of packagesubstrates and circuit boards may have a CTE of approximately 12 or more(again, a value that is temperature and composition dependent).Although, as noted above, the CTE of a substance is temperature andcomposition dependent, the CTE mismatch between a silicon die and theunderlying substrate is significantly reduced using a glass coresubstrate as compared to a polymer-based substrate material. Inaddition, glass may have a modulus, E, of approximately 75 GPA, whereascommonly used organic polymer-based materials may have a modulus ofapproximately 25 GPa (the value of E also being dependent upon thecomposition of a substance). Thus, a glass core substrate may provide athree-fold increase in modulus, which in some embodiments may providethe potential for a corresponding three-fold decrease in substratewarpage. A further advantage of glass is that it may be manufacturedwith more consistent flatness than common polymer materials.

The above-described reductions in CTE mismatch and warpage may enablethe use of a smaller pitch for die-to-package interconnects, as well asa larger number of these interconnects, providing increase I/Ocapability. For example, in one embodiment, a pitch of 50 micrometers orless may be achieved for die-to-package interconnects when using a glasscore substrate. Large substrate warpage may lead to non-contact-openfailures in the die-to-package interconnects during the chip attachprocess, as well as leading to high stresses within the die itself(e.g., within the inter-layer dielectric layers, or ILD layers, of thedie), both of which can result in lower reliability. Thus, the disclosedglass core substrate may enable the implementation of higher I/Opackages while, at the same time, maintaining or improving reliability.

The foregoing detailed description and accompanying drawings are onlyillustrative and not restrictive. They have been provided primarily fora clear and comprehensive understanding of the disclosed embodiments andno unnecessary limitations are to be understood therefrom. Numerousadditions, deletions, and modifications to the embodiments describedherein, as well as alternative arrangements, may be devised by thoseskilled in the art without departing from the spirit of the disclosedembodiments and the scope of the appended claims.

What is claimed is:
 1. A microelectronic substrate comprising: a corecomprised of solid glass, the solid glass core having a first surfaceand an opposing second surface; and a number of conductors extendingthrough the solid glass core beginning at the first surface and endingat the second surface.
 2. The microelectronic substrate of claim 1,wherein the number of conductors comprise a single conductive material.3. The microelectronic substrate of claim 2, wherein the number ofconductors comprise an opening through the solid glass core filled withthe single conductive material.
 4. The microelectronic substrate ofclaim 1, wherein the solid glass is selected from the group consistingof soda-lime glass, boro-silicate glass, alumo-silicate glass, fluorideglasses, phosphate glasses, chalcogen glasses, and pure silica.
 5. Themicroelectronic substrate of claim 1, wherein the conductors are formedfrom a material selected from the group consisting of copper, tin,silver, gold, nickel, aluminum, tungsten, and alloys of these and/orother metals.
 6. The microelectronic substrate of claim 1, furthercomprising: at least one dielectric layer and at least one metal layerat the first surface of the solid glass core, wherein the at least onemetal layer at the first surface is electrically coupled with at leastone of the conductors; and at least one dielectric layer and a least onemetal layer at the second surface of the solid glass core, wherein theat least one metal layer at the second surface is electrically coupledwith at least one of the conductors.
 7. A microelectronic package,comprising: a glass core substrate comprising a solid glass core havinga first surface and an opposing second surface, and a number ofconductors extending through the solid glass core beginning at the firstsurface and ending at the second surface; at least one dielectric layerand at least one metal layer at the first surface of the solid glasscore, wherein the at least one metal layer at the first surface iselectrically coupled with at least one of the conductors; at least onemicroelectronic device electrically coupled to the at least one metallayer at the first surface of the solid glass core; and at least onedielectric layer and a least one metal layer at the second surface ofthe solid glass core, wherein the at least one metal layer at the secondsurface is electrically coupled with at least one of the conductors. 8.The microelectronic substrate of claim 7, wherein the number ofconductors comprise a single conductive material.
 9. The microelectronicsubstrate of claim 8, wherein the number of conductors comprise anopening through the solid glass core filled with the single conductivematerial.
 10. The microelectronic substrate of claim 7, wherein thesolid glass is selected from the group consisting of soda-lime glass,boro-silicate glass, alumo-silicate glass, fluoride glasses, phosphateglasses, chalcogen glasses, and pure silica.
 11. The microelectronicsubstrate of claim 7, wherein the conductors are formed from a materialselected from the group consisting of copper, tin, silver, gold, nickel,aluminum, tungsten, and alloys of these and/or other metals.